1151

Nutr Hosp. 2013;28(3):1151-1155ISSN 0212-1611 • CODEN NUHOEQ

S.V.R. 318

Original / Pediatría

Physical activity and cardiorespiratory fitness in adolescentswith Down syndromeA. Matute-Llorente1,2, A. González-Agüero1,3, A. Gómez-Cabello1,2, G. Vicente-Rodríguez1,2 and J. A. Casajús1,2

1GENUD Research Group, University of Zaragoza. Zaragoza. Spain. 2Faculty of Health and Sport Sciences. University ofZaragoza. Huesca. Spain. 3Department of Sport and Exercise Science. Aberystwyth University. Ceredigion.

ACTIVIDAD FÍSICA Y ESTADO DE FORMACARDIOVASCULAR EN ADOLESCENTES

CON SÍNDROME DE DOWN

Resumen

Objetivos: Comprobar si los adolescentes con síndromede Down (SD) cumplen las guías de actividad física (AF) yevaluar la relación entre AF y la condición cardiorrespi-ratoria.

Métodos: 42 adolescentes (27 con SD) participaron eneste estudio. La AF se midió usando acelerometría. Lacondición cardiorrespiratoria se evaluó mediante ergoe-spirometría en tapiz rodante con un protocolo progresivocontinuo.

Resultados: Los adolescentes con SD pasaron menostiempo en AF sedentaria, moderada (MAF), vigorosa(VAF) y moderada-vigorosa (MVAF) que los adoles-centes sin SD. El VO

2peakmostró correlación con minutos

totales en AF ligera, MAF, VAF y MVAF en el grupo con-trol (desde r = 0,55 hasta r = 0,61, p < 0,05) y con MAF yVAF en el grupo de adolescentes con SD (desde r = 0,38hasta r = 0,41, p < 0,05).

Conclusión: Ningún grupo alcanzó 60 minutos de MAFdiaria. La capacidad cardiorrespiratoria en adolescentescon SD se asoció con una mayor participación en MAF.

(Nutr Hosp. 2013;28:1151-1155)

DOI:10.3305/nh.2013.28.4.6509Palabras clave: Acelerometría. Síndrome de Down. Activi-

dad física. Capacidad cardiorrespiratoria.

Abstract

Aims: To determine if adolescents with and withoutDown syndrome (DS) accomplish the physical activity(PA) guidelines and to evaluate relationships between PAand cardiorespiratory variables.

Methods: 42 adolescents (27 with DS) participated inthis study. PA was measured using accelerometers.Walking-graded treadmill protocol with a breath-by-breath gas analyzer was employed to assess cardiorespi-ratory fitness.

Results: Adolescents with DS spent less time in seden-tary PA, moderate PA (MPA), vigorous PA (VPA) andmoderate to vigorous PA (MVPA) than those without DS.VO

2peakwas correlated with total minutes spent in light

PA, MPA, VPA and MVPA in the control group (from r =0.55 to r = 0.61, p < 0.05) and with MPA and MVPA in theDS group (from r = 0.38 to r = 0.41, p < 0.05).

Conclusion: Nor DS neither control groups achieved atleast 60 minutes of MPA daily. Engaging more time inMPA was associated with greater cardiorespiratoryfitness in adolescents with DS.

(Nutr Hosp. 2013;28:1151-1155)

DOI:10.3305/nh.2013.28.4.6509Key words: Accelerometry. Down syndrome. Physical

activity. Cardiorespiratory fitness.

Introduction

Physical inactivity and sedentarism are risk factorsassociated with the development of obesity and havealso been linked to type 2 diabetes, stroke, cardiovas-

cular diseases, and some cancers.1,2 Children andadolescents with Down syndrome (DS) have beenshown as less active3 and with higher prevalence ofoverweight and obesity4 than those without DS but theinformation regarding physical activity (PA) in adoles-cents with DS is few and inconclusive.5

Current recommendations on PA such as: ThePhysical Activity Guidelines for Americans6 and theUK Chief Medical Officers7 recommend that childrenand adolescents engage in at least 60 min of dailymoderate PA (MPA) to achieve health-related bene-fits. Previous studies8-10 in DS populations show noconclusive results in relation to the levels of PA, and

Correspondence: José Antonio Casajús Mallén.GENUD Research Group.Ed. Cervantes. Corona de Aragón, St. 42, 2nd floor.50009 Zaragoza. Spain.E-mail: Joseant@unizar.es

Recibido: 15-II-2013.Aceptado: 16-V-2013.

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no research has been focused on Spanish adolescentswith DS. Furthermore, no specific PA guidelines foradolescents with DS which take into account theimpairment of this population such as muscle hypo-tonicity, low cardiovascular fitness and decreasedmuscle strength11 have been developed.

It is well known that cardiorespiratory fitness duringadolescence has a strong association with present andfuture health and cardiovascular diseases.12 Previousstudies have shown that individuals with DS havelower levels of cardiovascular fitness compared withtheir peers without DS;13 however, the relationshipbetween cardiorespiratory factors and PA remainsunknown in this determined population.

Therefore, the aims of this study were: (1) to deter-mine if adolescents with DS accomplish the PA guide-lines for health objectively assessed comparing theirPA patterns with adolescents without disabilities; (2) totest the relationship between PA levels and cardiovas-cular fitness in adolescents with DS.

Methods

Participants

A total sample of 27 adolescents with DS (13 girls/ 14boys; aged 10 to18 years) living at home, were recruitedfrom different special schools and institutions within theregion of Aragon in Spain. A control group composed of15 adolescents (8 girls/7 boys) without any disabilitywas also recruited from regular schools in the sameregion. Both parents and children were informed aboutthe aims and procedures of the study, as well as thepossible risks and benefits, and then, a letter of writteninformed consent was obtained from all the includedsubjects and their parents or guardians. The study wasperformed in accordance with the Helsinki Declaration1961 (revised in Edinburgh, 2000) and was approved bythe Research Ethics Committee of the Government ofAragon (CEICA, Spain).

Anthropometry

All participants were measured with a stadiometerwithout shoes and minimum clothing to the nearest0.1 cm (SECA 225, SECA, Hamburg, Germany) andweighted to the nearest 0.1 kg (SECA 861, SECA,Hamburg, Germany). The body mass index (BMI)was calculated as weight (kg) divided by heightsquared (m2).

Physical activity assessment

PA was measured using the ActiTrainer uniaxialaccelerometer (Actigraph, LLC, Pensacola, FL,USA). The monitor was set to record PA in a 15 epoch

which was selected on the basis of literature related tothe erratic and sudden bursts of activity common toyouth.14 Adolescents wore the accelerometer forseven consecutive days and was worn above the hipand fitted with an elastic waistband. Instructions weregiven to the participants and carers both verbally andin writing on how to wear the accelerometer during allwaking hours except while bathing, showering andswimming. To be included in the study, participantshad to wear the accelerometer for a minimum of 8hours per day, for at least 6 days.15 Minutes andpercentage of valid time in sedentary, light (LPA),moderate (MPA), vigorous (VPA), and moderate tovigorous PA (MVPA) intensities were calculatedfrom the raw data obtained from the accelerometer.The cut-offs proposed by Sirard et al.16 were used toestablish intensities. We also calculated time of bouts(bout = period of at least 5 min of consecutive MPA)and number of bouts.

Cardiovascular fitness assessment

Previous to maximal testing, an experienced cardiol-ogist examined each participant, giving permission toparticipate in the study. Participants were familiarizedwith the laboratory and testing protocols prior to anydata collection. Data collection started when partici-pants were able to easily walk on the treadmill (QuasarMed 4.0, h/p/cosmos, Nussdorf-Traunstein, Germany)with the mask fitted. A walking-graded protocol wasemployed to assess cardiovascular fitness. Starting at acomfortable walking pace for each participant (2.4 or3.2 km.h-1), speed was increased by 0.8 km.h-1 every 2min until participants were not able to walk withoutrunning (4.8 or 5.6 km.h-1). Then the grade wasincreased 4% every minute until exhaustion (until amaximum of 24%). A medical doctor, specialist insports medicine, supervised the whole test, and alsoexamined the participants prior exercising.

Respiratory gas-exchange data were measured“breath-by-breath” using an open circuit spirometry(Oxycon Pro, Jaeger/Viasys Healthcare, Hoechberg,Germany). Peak values of oxygen uptake (VO

2peak), are

recorded as the highest average values obtained for anycontinuous 30 s period. The metabolic cart was cali-brated with a known gas and volume prior to the firsttest each day as recommended by the manufacturer.Electrocardiogram (ECG) was used to record heartrate, utilizing a 12-lead system before, and during thewhole test. The maximal value of heart rate (HR

max) was

the highest value of heart rate recorded during the laststage of exercise.

Statistical analyses

All analyses were performed using the StatisticalPackage for the Social Sciences (SPSS 15.0 for

1152 A. Matute-Llorente et al.Nutr Hosp. 2013;28(4):1151-1155

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Windows; SPSS Inc, Chicago, IL) and significancewas set at p ≤ 0.05.

Mean and standard deviation were used to describethe characteristics of the participants and PA patternsamong groups. All variables included in the studyshowed normal distribution, assessed by Kolmogorov-Smirnov tests. Differences between groups (with andwithout DS) separately by genders and betweengenders within each group were established for age,height, weight and BMI using Student s unpaired t-tests. Analyses of covariance (ANCOVA) wereperformed to evaluate differences between groups inthe variables obtained from the accelerometer, usingage as covariate. Partial correlations adjusted for agewere applied to identify possible relationships betweenminutes of time spent in different PA intensities andcardiovascular parameters (VO

2peakand HR

max).

Results

Physical characteristics and cardiovascular fitness

Age, physical characteristics and cardiovascularparameters of the participants are summarized in tableI. In general, participants with DS were older andsmaller than those without DS (all p ≤ 0.05). Nodifferences in weight and BMI were observedbetween groups or between genders within the samegroup. Within DS group, females were smaller thanmales; however, no differences were found betweengenders in the control group.

Differences in VO2peak

and HRmax

were observedbetween groups. Within control group, females showedlower VO

2peak than males; no differences in HR

maxwere

found between genders. In DS group, no differences inany cardiovascular parameters were found betweengenders.

Physical activity recommendations

Following the recommendations stated above6,7 noneof the two groups achieved the minimum of 60 minutesof MPA daily.

Physical activity

Significant differences between adolescents with andwithout DS regarding PA patterns were observed; thosewith DS engaged significantly less minutes in sedentaryPA, MPA, VPA and MVPA than their counterpartswithout DS (all p < 0.05; fig. 1). However, adolescentswith DS engaged more minutes in LPA (all p ≤ 0.05; fig.1). Moreover, less total counts, time and number of bouts,and steps were observed in the DS group compared withcontrol group (all p ≤ 0.05; data not shown).

Correlations PA-Cardiovascular fitness

In the control group, VO2peak

was correlated withminutes spent in LPA, MPA, VPA and MVPA (r =

Physical activity and cardiorespiratory

fitness in adolescents with Down

syndrome

1153Nutr Hosp. 2013;28(4):1151-1155

Table IDescriptive data for participants

Down syndrome Control

All (n = 27) Female (n = 13) Male (n = 14) All (n = 15) Female (n = 8) Male (n = 7)

Age (years) 16.2* ± 2.9 15.8 ± 3.2 16.5 ± 2.7 13.6 ± 3.0 13.3 ± 3.1 14.0 ± 3.1

Weight (kg) 48.8 ± 12.2 46.1 ± 12.5 51.2 ± 11.9 50.4 ± 15.1 47.3 ± 13.2 54.0 ± 17.4

Height (cm) 147.1* ± 11.3 141.3# ± 9.6 152.4 ± 10.4 156.0 ± 14.5 150.3 ± 10.8 162.6 ± 16.2

Body mass index (kg/m2) 22.2 ± 3.6 22.7 ± 4.1 21.8 ± 3.1 20.3 ± 3.6 20.7 ± 3.9 19.9 ± 3.5

VO2max

(mL/kg/min) 35.5* ± 6.4 33.6 ± 7.4 37.3 ± 4.9 43.1 ± 5.0 40.8# ± 5.8 45.8 ± 1.9

HRmax

170.9* ± 13.3 166.5 ± 16.4 175.1 ± 8.1 191.2 ± 7.8 190.1 ± 8.8 192.5 ± 7.0

*p ≤ 0.05 between groups.#p ≤ 0.05 between sexes within the same group.

*

*

**

*

Fig. 1.—Age-adjusted total minutes of PA for adolescents withand without DS; * p ≤ 0.05.

ControlDown syndrome

Sedentary Light MVPA Moderate Vigorous

800

600

50

0

Min

utes

of P

A

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0.55; 0.57; 0.61 and 0.61 respectively; all p ≤ 0.05; datanot shown). In the DS group, VO

2peakwas correlated

with minutes spent in MPA and MVPA (r = 0.41 andr = 0.38; both p ≤ 0.05; data not shown); in addition,HR

max was correlated with minutes spent in MVPA (r =

0.38; p ≤ 0.05; data not shown).

Discussion and conclusion

This study provides data on objectively measuredPA and thereby provides valuable information aboutthe PA levels and its relationship with cardiorespira-tory fitness of adolescents with and without DS.

Different PA patterns were found between adoles-cents with and without DS in this study. Adolescentswith DS presented higher levels of LPA and lowersedentary PA, MPA and VPA than adolescents withoutDS. To our knowledge, it is the first time that theseresults are found. Data in DS population are scarce anddissimilar.

Phillips et al.8 showed that individuals with DSspend more sedentary time than those without DS. Incontrast, similar levels of sedentary, LPA and MPAin children with and without DS were registered inthe study performed by Whitt-Glover et al.10 In ourstudy, adolescents with DS engaged less minutes inMPA and MVPA than those without. A possibleexplanation could be the age difference, being ourstudy focused on adolescents and the previous inchildren. This is in concordance with previous resultswhere adolescents with DS aged 14 to 15 were moresedentary and spent less time in MVPA comparedwith children with DS.9 Caution is needed whenmaking comparison between studies as they differ inaccelerometer models and cut-offs used. Neither ofthe previous studies used the same model ofaccelerometer or equal cut-off points. It would be,therefore interesting to establish specific cut-offs forpopulation with DS.

Following another guidelines,17 Whitt-Glover foundthat most children with DS exceeded the guidelinesof PA.10 However, following the guidelines statedabove (children and adolescents should perform atleast 60 minutes of MPA daily);6,7 in our study, noneof the two groups achieved these recommendations(DS 9.2 min, control 15.4 min) nor the recommended30-min of MPA either. Other studies found similarresults.8,9

In this study VO2peak

showed moderate correlationswith total minutes in LPA, MPA, VPA and MVPA inthe control group. In the DS group, HR

max was only

correlated with total minutes of MVPA. At the sametime, moderate correlations between VO

2peak, MPA and

MVPA were observed in the DS group and no correla-tions were found between VO

2peakand minutes spent in

LPA or VPA. It could be due to the low time spent invigorous intensity activities (with Sirard cut-offs) byadolescents with DS. It might be also thought that this

cut-offs are not the most appropriate for children withDS as they have worse walking economy and a lowerphysical fitness.

Thereby, strategies aiming to increase MPA inadolescents with DS should be promoted as they maybe at higher risk of developing diseases associated withphysical inactivity such as osteoporosis or metabolicsyndrome.11 In addition, we could speculate that thesestrategies could improve cardiovascular fitness inadolescents with DS, being this fact relevant forreducing future cardiovascular diseases.

There are some potential limitations to this studythat warrant consideration. Firstly, the cut-offs thatwere used to define the intensity of PA were gener-ated to study preschool children without disabilitiesand may over- or under-estimate intensity of PAamong adolescents with DS. Despite both groupswas made up of adolescents, the age differencebetween groups was significant. Also the number ofparticipants might be limiting the statistical power ofthe analyses.

In conclusion, nor DS neither control groupsachieved the recommended 60 minutes of MPA daily.Different PA patterns were found between DS andcontrol groups. Adolescents with DS engaged less timein sedentary PA, MPA, MVPA and VPA than theircounterparts without DS but they achieved moreminutes in LPA. Engaging more time in MPA andMVPA is associated with greater cardiorespiratoryfitness in adolescents with DS.

Acknowledgements

We gratefully acknowledge the help of all of theadolescents and their parents who participated in thestudy for their understanding and dedication to theproject. Specials thanks are given to Fundación DownZaragoza and Special Olympics Aragón for theirsupport. This work was supported by ‘Ministerio deCiencia e Innovación’ ‘Plan Nacional I+D+i 2009-2011 (Project DEP 2009-09183)’. This project hasbeen co financed by “Fondo Europeo de DesarrolloRegional” (MICINN-FEDER). AML received a GrantFPU12/02854 for the “Ministerio de EducaciónCultura y Deportes”. These authors declare that theyhave no conflicts of interest that may affect thecontents of this work.

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